I certainly would have in his shoes. Then again, maybe he was getting pressured a little to make a decision. I mean, we ourselves have complained about guys being signed just days before camp.i think the point is if he really wanted to stay, he would have at least given the new guy a chance. Unless he had already committed to another team and accepted an offer, if he really wanted to stay, I think it's reasonable to at least hear the new guy out.
Perhaps the Galaxy were like, "Hey man, we're coming with a much bigger number than anything they've put in front of you, but we don't want to wait until the last minute. We have alternatives where we can spend it." If you're in Justin's shoes, do you want to gamble on Dunivant coming with the same number? Especially if you feel like you've been lowballed and getting strung along.
I don't know if that was the case, or it was a matter of David Lee dithering, or if it was just too good a deal to pass up. Maybe it's all three.